How Do Teeth Whiteners Work?

Tooth whitening is an $11 billion industry in the U.S., with products used by more than 12 percent of American households every year. We’re definitely shelling out for whiter teeth—but are we getting them?

Sort of. As the video above from the American Chemical Society explains, whitening products vary in effectiveness. Nearly all commercial products—from the treatments administered by dentists to at-home whitening strips and mouthwashes—include hydrogen peroxide. The efficacy of these products depends on three things: how long they stay on your teeth, how concentrated they are, and the source of the discoloration on your teeth. If you use a concentrated product as it’s meant to be used, you will likely see a brightening effect.

Unfortunately, this effect is temporary. "Once you stop with the bleach, it regresses—your teeth start returning to their original color," American Society for Dental Aesthetics president Irwin Smigel toldPrevention. "Very few people are happy with the color once it starts regressing, so they'll do teeth whitening again and again."

Also, these products are not intended for long-term use. They’re mostly safe in small doses, but over time, soaking your teeth in a bleaching agent can hurt your gums and teeth.

"Ten years ago, people weren't even aware of bleaching," Smigel said. "Now every dentist I know has had to cut off at least one patient because of overbleaching. People come in with great, great pain, and I can see immediately from the color of their teeth and the irritation along the gums that they've been bleaching and bleaching."

If a lifetime of bleaching is off the table, what about all those “natural” whitening remedies you see online? Dentists agree that baking soda is safe as long as you also brush your teeth with toothpaste, but it can only scrub your teeth, not brighten them.

And then there are the fruit remedies recently touted by Dr. Oz, who declared that brushing with a mixture of strawberries and baking soda can whiten teeth. Do not do this. Scientists tested the mixture on extracted human teeth and declared it a real dud. Not only does the strawberry/baking soda combo not brighten teeth, but it actually hurts them. A naturally occurring strawberry compound called malic acid eats away at teeth’s enamel, making them softer.

If white teeth are important to you, there are two things that will always help: regular brushing and flossing.